U.S. patent number 4,997,876 [Application Number 07/302,687] was granted by the patent office on 1991-03-05 for flame-retarding composition for polymers and self-extinguishing polymeric products so obtained.
This patent grant is currently assigned to V.A.M.P. S.r.l.. Invention is credited to Luciano Scarso.
United States Patent |
4,997,876 |
Scarso |
* March 5, 1991 |
Flame-retarding composition for polymers and self-extinguishing
polymeric products so obtained
Abstract
Flame-retarding composition for rendering self-extinguishing
polymers, copolymers, mixtures of polymers and various polymeric
materials, comprising a polymer, a copolymer, or a mixture of
polymers of hydroxyalkyl-derivatives of isocyanuric acid and
ammonium polyphosphate, and so-obtained self-extinguishing polymers
and polymeric materials.
Inventors: |
Scarso; Luciano (Milan,
IT) |
Assignee: |
V.A.M.P. S.r.l. (Milan,
IT)
|
[*] Notice: |
The portion of the term of this patent
subsequent to February 23, 2005 has been disclaimed. |
Family
ID: |
11184033 |
Appl.
No.: |
07/302,687 |
Filed: |
January 18, 1989 |
PCT
Filed: |
June 30, 1988 |
PCT No.: |
PCT/EP88/00571 |
371
Date: |
January 18, 1989 |
102(e)
Date: |
January 18, 1989 |
PCT
Pub. No.: |
WO89/01011 |
PCT
Pub. Date: |
February 09, 1989 |
Foreign Application Priority Data
|
|
|
|
|
Aug 4, 1987 [IT] |
|
|
21690 A/87 |
|
Current U.S.
Class: |
524/706; 523/205;
523/451; 523/506; 524/416; 524/868 |
Current CPC
Class: |
C08K
3/32 (20130101) |
Current International
Class: |
C08K
3/00 (20060101); C08K 3/32 (20060101); C08K
003/32 () |
Field of
Search: |
;523/205,451,506
;524/416,868,706 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Jacobs; Lewis T.
Attorney, Agent or Firm: Collard, Roe & Galgano
Claims
I claim:
1. A flame retardant composition for polymeric materials
comprising
a polymer derived from the polymerization of a hydroxyalkyl
derivative of isocyanuric acid monomer and ammonium polyphosphate,
said ammonium polyphosphate having the general formula
(NH.sub.4).sub.n+2 P.sub.n O.sub.3n+1 wherein n is a number higher
than 20;
said ammonium polyphosphate being uniformly and intimately
incorporated into said polymer of said hydroxyalkyl derivative of
isocyanuric acid; and
said ammonium polyphosphate being mixed with the monomer of said
hydroxyalkyl derivative of isocyanuric acid in the presence of a
condensation-etherification catalyst before or while the
polymerization of said monomer is carried out.
2. A flame retardant composition according to claim 1,
wherein said hydroxyalkyl derivative of isocyanuric acid is
tris-(2-hydroxyethyl)-isocyanurate.
3. A flame retardant composition according to claim 1,
wherein said ammonium polyphosphate is ammonium polyphosphate
having the general formula (NH.sub.4).sub.n+2 P.sub.n O.sub.3n+1,
wherein n is a number from 1 to 20.
4. A flame retardant composition according to claim 1,
wherein said flame retardant composition is constituted by 10 to
90% by weight of said polymer of said hydroxyalkyl derivative of
isocyanuric acid and 90 to 10% by weight of said ammonium
polyphosphate.
5. A flame retardant composition according to claim 1,
wherein said composition is mixed with from 10 to 30% by weight of
a wax, or of a polymeric substance; and
the polymeric material to which said composition is added,
performing the function of a bonding-carrier agent; and other
additives are selected from the group consisting of a coadjuvant, a
dye, a lubricant and an antistatic agent.
6. In a method for adding an agent to render polymers or copolymers
self-extinguishing, the improvement comprising utilizing the flame
retardant composition according to claim 1 as said agent,
and wherein said polymers or copolymers are selected from the group
consisting of polyethylene, polypropylene, ethylene-propylene
rubbers, polystyrene, impact-resistant polystyrene, ABS resins, SBS
resins, polyurethanes, epoxy resins, unsaturated polyesters,
paints, sizes for fabrics, and latexes for carpets.
7. A polymeric material endowed with self-extinguishing properties
comprising the flame-retardant composition according to claim 1.
Description
DESCRIPTION
The present invention is concerned with a "flame-proofing" or
"flame-retarding" composition for polymers, copolymers and blends
of such polymers as polyolefins, polystyrenes, polyurethanes, etc.,
as well as thermosetting epoxy resins, polyesters, and the
like.
An object of the invention are also the polymers, copolymers,
polymeric mixtures and the thermosetting resins, as well as
miscellaneous polymeric materials, such as paints, fabrics and the
like, rendered self-extinguishing by means of said flame-retarding
composition.
It is known that a generic polymeric material is made
"self-extinguishing" or "flame-proof" or "flame-resistant" by means
of the addition of particular "flame-proofing" or "flame-retarding"
agents, which are precisely capable of endowing the polymeric
substance with the required characteristics of self-extinguishment.
Such flame-proofing agents are constituted by halogenated, usually
brominated, organic substances, metal compounds (in particular
oxides, such as, e.g., antimony trioxide), phosphorus and its
derivatives (such as, e.g., red phosphorus, ammonium polyphosphate,
organic phosphoric esters), miscellaneous nitrogen-containing
compounds (such as, e.g., urea, dicyandiamide, melamine), and still
others. It is known that in some cases, in order to reach the
desired characteristics of self-extinguishment in a polymer, even
two or more different flame-proofing compounds are used in
association with each other, both in order to exploit, in
combination, specific flame-proofing characteristics and/or
"functions", and to accomplish determined particular "synergistic"
or "combined" effects, and to avoid adding excessively high amounts
on an individual flame-proofing agent, necessary to reach the
desired level of self-extinguishment in the polymer, but which
would involve an alteration or degradation of the same polymer, due
to the typical characteristics of the flame-proofing agent
used.
It is well known indeed that when a self-extinguishing polymeric
material has to be accomplished by incorporating into it one or
more flame-retarding agents, the amounts of said agents in the
above-said material have to be limited as extensively as possible,
in order not to appreciably alter the chemical-physical and
mechanical characteristics of the same material.
It is furthermore known that a loss (escape) by extraction and/or
dissolving of the flame-retarding agents added to said materials,
and the "ageing" of said agents--in terms of a loss of
flame-retarding power of the same agents as a function of time
and/or particular chemical and/or physical factors of the
surrounding environment--occurs.
Flame-retarding compositions of known type are those constituted by
a hydroxyalkyl-derivative of isocyanuric acid, viz., a
nitrogen-containing cyclic product, in particular
tris-(2-hydroxyethyl)-isocyanurate, in association with other two
components, viz., with a phosphorus-based product, such as ammonium
polyphosphate, and another nitrogen-containing product, such as
melamine, cyanuric acid, melamine salts, e.g., melamine cyanurate
(European patent application No. 0204027 and U.S. Pat. No.
4,198,493). It can be seen that these are three-component
flame-retarding compositions, based on phosphorus and nitrogen,
suitable for being used in order to render self-extinguishing the
polyolefinic and/or polystyrenic polymers.
A purpose of the present invention is to provide a flame-retarding
composition constituted by two components only, which can be used
in the necessary amounts and mutual ratios to reach the desired
degree of self-extinguishment in the polymer, without phenomena
occurring of alteration and/or degradation of the chemical-physical
and mechanical characteristics of the polymer, due to the presence
of several flame-proofing agents.
Another purpose of the present invention is to provide a
flame-retarding composition for polymers, which is stable over
time, and to the external environmental agents, and which,
therefore, does not give rise to losses due to the extraction
and/or dissolving of the flame-proofing agents introduced in the
polymer.
Still another purpose of the present invention is to provide a
flame-retarding composition for general use, i.e., which can be
advantageously used for a very wide range of polymeric materials,
comprising the polyolefins, the styrenic polymers, the
polyurethanes, the epoxy resins, the unsaturated polyesters, and
the like.
These and still further purposes and related advantages, which will
be evidenced by the following disclosure, are advantageously
achieved by a flame-retarding composition for polymers, copolymers,
mixed polymers and therewith obtained polymeric materials, which
composition, according to the present invention, comprises the
following components:
(A) a polymer, a copolymer or a mixture of polymers and/or
copolymers of the hydroxyalkyl-derivatives of isocyanuric acid,
having the formula ##STR1## wherein R', R" and R'" are alkyl
radicals, equal to, or different from, each other, containing from
1 to 6 carbon atoms.
(B) ammonium polyphosphate, having the general formula
wherein n is a number higher than 20. We were able to observe, in
fact, that the hydroxyalkyl-derivatives of isocyanuric acid, when
in polymerized form, perform their flame-proofing action in
association with phosphorus-containing agents, without causing
substantial alterations in the chemical-physical and/or mechanical
characteristics of the polymer in which they are incorporated, and
without the occurrence of dissolving, migration, extraction
phenomena, and the like. Therefore, with the other conditions being
the same, the use of the isocyanuric acid hydroxyalkyl-derivative
in the polymerized form, according to the present invention, makes
it surprisingly possible the desired levels of self-extinguishment
to be reached in the polymers in which said polymer derivative is
introduced in association with phosphorus derivatives, with no need
to resort to the association of other nitrogenous products such as
e.g., urea, dicyandiamide, melamine and/or salts thereof, such as,
e.g., the cyanurate, and so forth, whose use is known to cause
considerable and serious drawbacks to the detriment of the
chemical, physical and mechanical characteristics of the polymeric
material endowed with the self-extinguishing characteristics.
Furthermore, and still more surprisingly, we were able to observe
that the flame-retarding composition according to the present
invention is suitable for general use, and can be advantageously
used for polyolefinic polymers, copolymers and mixed polymers (such
as polyethylene, polypropylene, ethylenepropylene rubbers, etc.),
for styrenic polymers (such as polystyrene, impact-resistant
polystyrene, SBS, ABS resins, etc.), for polyurethanes, for
thermosetting resins, such as epoxy resins and unsaturated
polyesters. The composition according to the invention can be
furthermore used for the purpose of rendering self-extinguishing
various polymer-based materials, such as, e.g., the paints, the
fabrics, the sizes for r fabrics, the adhesives, the latexes for
carpets, and the like.
Preferably, as the (A) component of the composition according to
the invention, the polymer of tris-(2-hydroxyethyl)-isocyanurate is
used, which is polymerized according to known processes, e.g., by
heating the monomer in the presence of a suitable
condensation-etherification catalyst, according to as reported in
U.S. Pat. No. 3,293,224.
According to the present invention, the (B) component, i.e., the
ammonium polyphosphate, is preferably used in the form of particles
microencapsulated (according to known processes) in a
water-repellent synthetic resin, or the like, in particular when
the composition according to the present invention is destined to
render self-extinguishing polymeric materials for electrical
applications, for uses requiring low water absorption by the same
materials, and when a high resistance to water-extraction is
required.
Still according to the present invention, the (B) component can be
mixed with the monomer of the hydroxyalkyl-derivative of
isocyanuric acid before and/or while the polymerization of said
monomer is carried out, e.g. by heating a previously prepared
mixture of hydroxyalkyl-derivative of isocyanuric acid and ammonium
polyphosphate in the presence of the condensation-etherification
catalyst, so obtaining a flame-retarding composition (A+B) in which
the (B) component is intimately and uniformly incorporated into the
(A) component. Consequently, the distribution of the flame
retardant composition into the polymer to be rendered
self-exstinguishing results yet easier and more effective.
It has been seen that, when the ammonium polyphosphate is so
incorporated into the (A) component, the flame-retarding
composition can be advantageously used for rendering
self-extinguishing polymeric materials for electrical applications
and in general when low water absorption and/or high resistance to
water-extraction is required, even without the use of the above
mentioned microencapsulated form for said ammonium polyphosphate.
Furthermore, it has also been surprisingly seen that a
(NH.sub.4).sub.n+2 P.sub.n O.sub.3n+1 can be advantageously used in
which n is a number lower than 20, and even equal to 1.
The amounts, and the ratio of the (A) and (B) components to be
incorporated in the polymer, or in the polymeric material, to
efficaciously endow it with self-extinguishing characteristics,
vary as a function of the same polymer. In general, in order to
reach a satisfactory self-extinguishment level, in the polymer the
following amounts are used of the two components, expressed as
percentages by weight relatively to the polymer endowed with
self-extinguishing characteristics:
(A) isocyanuric acid hydroxyalkyl-derivative polymer: from 1 to
40%;
(B) ammonium polyphosphate: from 1% to 60%.
The flame-proofing composition according to the invention, when
referred to the total of the same composition, is constituted by
the following weight percentages of the two components:
(A) isocyanuric acid hydroxyalkyl-derivative polymer: from 10 to
90%;
(B) ammonium polyphosphate: from 90% to 10%.
The components (A) and (B) of said flame-retarding composition may
be mixed with from 10 to 30% by weight of a wax, or of a polymeric
substance of the same nature as, or any way compatible with, the
polymer to which said flame-retarding composition is added,
performing the function of a bonding-carrier agent, and/or with
other additives, such as various coadjuvants, dyes, lubricants, and
antistatic agents of known type.
The total amounts of the composition according to the invention to
be incorporated in the polymeric materials are of the order of from
5 to 70% by weight (relatively to the total). For example, in
polypropylene, approximately 20-40% thereof are incorporated; in
polyethylene, 25-45% thereof, and in ABS resins 30-50% thereof are
incorporated; thus, self-extinguishing materials of V-0 grade
according to UL-94 (Underwriter Laboratories, U.S.A.) being
obtained.
The flame-retarding composition according to the invention makes it
possible to simultaneously use, in the polymer undergoing the
self-extinguishment treatment, stabilizer-antioxidant agents of
known type, lubricants, dyes, inorganic fillers, mineral fibres,
and the like.
The constituents of the flame-proofing composition according to the
invention are incorporated in the polymers according to known
techniques, which may vary from case to case, as a function of the
polymer. For instance, in case of a polyolefinic polymer, the
incorporation can be carried out by melt-blending in the plastic
state into screw extruders.
The present invention can be better evidenced and disclosed by the
following examples of practical embodiment thereof, which are
supplied for the purpose of merely illustrating and not limiting
the scope of protection of the same invention.
EXAMPLE 1
On a mechanical mixer, a blend was prepared, consisting of 69.8% of
polypropylene (MFI=12), 15% of tris-(2-hydroxyethyl)-isocyanurate
polymer, "A" component according to the invention, 15% of "B"
component--ammonium polyphosphate microencapsulated with epoxy
resin (EXOLIT 455 by Hoechst)--and 0.2% of antioxidant (IRGANOX
1010).
The blend was subsequently mixed and melted to the plastic state
into a screw extruder, and cylindrical granules of 3.times.3 mm
were obtained, which were ready to be transformed into finished or
semi-finished shaped articles by means of conventional fabrication
procedures, e.g., injection-moulding, and extrusion. The
so-obtained polypropylene (denominated as the "a" sample), was
submitted to the tests for self-extinguishment, and to the
mechanical tests for characterization, whose results are reported
in Table 1.
On the same mechanical mixer, a blend was prepared, for comparison
purposes, which was constituted by 69.8% of polypropylene, 15% of
ammonium polyphosphate EXOLIT 455 and 0.2% of antioxidant, but
using, instead of tris-(2-hydroxyethyl)-isocyanurate polymer, 7.5%
of tris-(2-hydroxyethyl)-isocyanurate as such, in monomer form
(soluble in water), and 7.5% of melamine cyanurate. From the
so-prepared blend, on a screw extruder cylindrical granules were
obtained, from which the samples (denominated "b" sample) were
prepared, which were submitted to the self-extinguishment tests,
and to the mechanical characterization tests, whose results are
also shown in following Table 1. It can be seen that in both cases
a satisfactory level of self-extinguishment was reached, but the
mechanical characteristics of the "a" sample, obtained by using the
flame-proofing composition according to the present invention,
result definitely higher than of "b" sample, obtained according to
the known techniques. Furthermore, the "b" sample loses its
self-extinguishing characteristics when undergoing an extraction
with boiling water. Furthermore, the "a" sample is nearly
transparent, whilst the "b" sample is opaque. This indicates a
better dispersion in the "a" sample of the flame-proofing additives
throughout the polymeric matrix.
TABLE 1 ______________________________________ "a" Sample "b"
Sample ______________________________________ COMPOSITION
Polypropylene (MFI = 12) 69.8% 69.8% Microencapsulated ammonium 15%
15% polyphosphate (EXOLIT 455) Tris-(2-hydroxyethyl)- 15% --
isocyanurate polymer Tris-(2-hydroxyethyl)- -- 7.5% isocyanurate
monomer Melamine cyanurate -- 7.5% Antioxidant (IRGANOX 1010) 0.2%
0.2% TEST RESULTS Self-extinguishment (UL 94-V) V-0 V-0
Self-extinguishment after V-0 burns extraction with boiling water
Appearance translucent opaque Temperature resistance 103.degree. C.
81.degree. C. (VICAT)(ASTM D1525) Elongation at break 55% 17% (ASTM
D638) Impact strength (IZOD 20 12 without notch) (ASTM D256), kg
cm/cm ______________________________________
EXAMPLE 2
495 g of tris-(2-hydroxyethyl)-isocyanurate monomer were melted to
150.degree. C. Slowly and under stirring, 5 g of toluensolphonic
acid were added. Still under stirring, and maintaining the
temperature at 150.degree. C., 500 g of ammonium phosphate,
commercial grade, were added slowly to the melted mass.
A viscous mass is so obtained, which is maintained at 190.degree.
C. for 5 h under vacuum. The composition (A+B) obtained is cooled
at room temperature and then finely ground, at approximately 80
.mu.m.
On a mechanical mixer a blend was prepared consisting of 69.8% of
polypropylene (MFI=12), 30% of said composition (A+B) and 0.2% of
antioxidant (IRGANOX 1010).
The blend was mixed and melted to the plastic state into a screw
extruder, and cylindrical granules of 3.times.3 mm, as in the
Example 1, were obtained. The so obtained polypropylene was
submitted to the tests for self-extinguishment and to mechanical
tests for characterization, whose results are the following:
______________________________________ Self-extinguishment (UL
94-V) V-0 Self-extinguishment after extraction V-0 with boiling
water Appearance Translucent Temperature reisistance 150.degree. C.
(VICAT)(ASTM D1525) Elongation at break (ASTM D638) Impact strength
(IZOD without notch) 25 Kg cm/cm (ASTM D256)
______________________________________
EXAMPLE 3
A blend is prepared, which is constituted, in % by weight, by 60%
of ABS resin, 15% of "A" component and 25% of "B" component, said
blend being obtained and fabricated in granular form, by operating
as in Example 1. Also this polymeric product (like that from
Example 1, "a" sample), results to be self-extinguishing of V-0
grade (UL-94), both before and after the extraction with boiling
water.
EXAMPLE 4
A blend is prepared, which is constituted, in % by weigh, by 60% of
ABS resin, 40% of composition (A+B), prepared as in Example 2,
wherein the ratio of the "A" component to the "B" component is
equal to 1:1,7, said blend being obtained and fabricated in
granular form, by operating as in Example 2.
Also this polymeric product results to be self-extinguishing of V-0
grade (UL-94), both before and after the extraction with boiling
water.
EXAMPLE 5
A blend of polyol and toluenediisocyanate was prepared in the
ratios normally used to obtain polyurethanes for foaming processes.
To said blend, an amount of 20% by weight is added of the
flame-proofing composition according to the invention, wherein the
ratio of the "A" component, tris-(2-hydroxyethyl)-isocyanurate
polymer, to the "B" component is equal to 1:5. The so-obtained
product shows to be self-extinguishing of Class B1 according to DIN
4102, after the specimens of the material undergoing a hot-water
extraction treatment.
EXAMPLE 6
To 100 parts by weight of a polyester resin dissolved in 30 parts
of monomeric styrene, 60 parts by weight is added of a mixed
flame-proofing composition according to the invention, wherein the
ratio of the "A" component to the "B" component is equal to 3:2.
The product, suitably crosslinked by means of known crosslinking
agents, results to be self-extinguishing according to UL-94 V-0,
and ASTM D229 (method 2).
EXAMPLE 7
To 100 parts of epoxy resin prepolymer, 45 parts by weight is added
of a mixture constituted by 20 parts of "A" component, and 25 parts
of "B" component. Said composition is then polymerized and set with
catalysts according to the known processes, on the vertical
press.
The so-obtained polymer results to be endowed with V-0 grade
self-extinguishing properties according to UL-94 method.
EXAMPLE 8
A paint formulation having the following composition:
______________________________________ Water 30.6 parts by weight
"A" Component 14.2 parts by weight "B" Component 24.2 parts by
weight Polyvinyl acetate 20.0 parts by weight (Emulsion at 60% of
solids) Chloroparaffins 3 parts by weight TiO.sub.2 6.0 parts by
weight Emulsifiers, surfactants 2 parts by weight
______________________________________
was submitted to the combustion test. The paint resulted to be
intumescent.
EXAMPLE 9
To 100 parts by weight of a chlorovinylic resin at 60% of dry
matter, 20 parts by weight is added of a mixture constituted by 10
parts of "A" Component, and 15 parts of "B" Component.
The so-obtained emulsion was coated on the weft of an acrylic
fabric. After drying, the fabric underwent the DIN 4102 test, and
resulted to belong to B1 Class. Furthermore, according to the
invention, in order to facilitate the metering (absence of dusts)
and the dispersion of the flame-retarding composition in the
polymeric materials to be endowed with self-extinguishing
properties, said composition can be compounded and granulated with
an amount of 10-30% of a wax, or of a polymeric substance
compatible with the polymer to which it must be added, which
performs the function of a bonding-carrier means for the
flame-retarding components, as well as with other optional
conventional additives, such as coadjuvants, dyes, lubricants,
antistatic agents, inorganic fillers, and the like.
In this way, a "concentrate/supported composition" (known as a
"masterbatch") of the above-said flame-retarding agent, ready to be
added to the polymers, is formed.
To the invention, as hereinabove disclosed and illustrated,
technically equivalent variants can be possibly supplied, all of
them being within the protection of the same invention.
* * * * *